Method and means for automatically



W. J. MILLER Dec. 24, 1940;

METHOD AND MEANS FOR AUTOMATICALLY FEEDlNG AND FORMING PLASTIC MATERIAL IN THE MANUFACTURE OF POTTERY Original Filed Jan. 5, 1927 Smnntor 55 WZL/AMJ/WZEH 5 a Gttoizg Reissued Dec. 24, 1940 R 21,672

UNITED STATES PATENT OFFICE METHOD AND MEANS FOR AUTOMATICALLY FEEDING AND FORMING PLASTIC MATE- RIAL IN THE MANUFACTURE OF POTTERY William J. Miller, Swissvale, Pa.

Original No. 1,769,528, dated July 1, 1930, Serial No. 159,153, January 5, 1927. Application for reissue March 26, 1937, Serial No. 133,164

17 Claims. (CI. 25-22) This invention relates to an improved method insures a firm mechanical bond between the clay and means for automatically feeding and formand mold not impaired by entrapped air and a ing plastic material in the manufacture of bond which promotes the equal absorption of pottery. shrinkage water by the mold. This step of press- This application is a division of my co-pending ing out the clay in the mold after charging and 5 application Serial No. 32,753, filed July 18, 1935, before jiggering is novel to the production of for the reissue of my United States Letters Patware of this class in absorbent molds and when ent.No. 1,769,528 and relates specifically to a the clay is jiggered, the tendency of the bat to method and means for applying plastic mateslip is minimized and because of a minimum of i0 rial to molds in the manufacture of pottery. clay in the bat the amount of excess requiring re- According to th manual system of ware fabrimoval is reduced and hence the time required to cation on a potters wheel, the batter out pinches remove it. This contributes to accelerating the oil gobs of plastic clay at random, from a slug, jiggering operation and promotes the higher proflattens the same into the form of a pancake" of duction speeds contemplated with apparatus of a diameter insuring completev coverage of the this nature.

ware forming surface of a mold when applied The present method, in more general terms, thereto; and then deposits the same on a mold consists in covering a portion of the ware forming the clay sticking thereto due to its adhesive nasurface of a mold with clay in an amount, at least ture, after which the potter jiggers the clay and suflicient to form a ware body, then spreading the sets the mold aside for subsequent transportation clay over the ware forming surface by pressing, as 20 by a mold runner to the stove room. Air entrapwith a die to flow the clay towards the periphery ment between the pancake and mold often occurs of the mold, preferably in all directions simulpreventing the establishment of a complete and taneously to completely cover the total area of perfect state of eapillarity over the engaging surthe ware forming surface and adhesively bond faces of clay and mold so necessary to promote the clay to the mold surface and then smoothing 25 proper drying. The clay normally adheres to the the surface of the clay as by jiggering with a promold, but often creeps or slips under the drag of file tool. The radial progressive spreading acthe profile tool due to insufficient bonding. tion of the clay from the central zone of the mold In the production of flat and hollow ware, as toward the periphery prevents air entrapment heretofore manually practiced, an attendant segcommon to manual bat application and at the 30 regates gobs of clay from a conditioned mass and same time the clay is adhesively bonded to the throws the same into the bottom of the hollow mold by the pressure required to spread, setting mold without batting the same out or further up a bond of greater efficiency and one not liable processing it. The mold is spun on the potter's to allow slippage of the clay on the mold and one wheel at a relatively high R. P. M. and upon inthat will maintain the bond unimpaired when 35 troduction of the jiggering tool, the clay is spread under the profile tool. through the combined action of the tool and cen- Means are also provided in the present instance trifugal force. The inherent stickiness of the for rotating and raising and lowering any one or clay causes it to cling to the sides of the mold and all of the chucks independently or as a unit, to .40 establish a mechanical bond of probiematical similarly raise and lower and rotate the mold in o emciency but sufficient to promote the capillary timed relation to the preforming means, while the absorption of shrinkage water by the mold. The charge is being subjected to either of the forejiggering tool distributes the clay over the moldgoing operations. ing surface and tends to throw it outwardly and Fig. 1 is a side elevation, partly in section, of a upwardly toward the brim where the excess is repreferred form of mechanism for carrying out my 5 moved by the potter. improved method.

In the production of ware of this class accord- Fig. 2 is a top plan view of a part of the mechaing to the present invention, molds are automatinism. cally charged with clay, each charge being of Fig. 3 is an elevation 01' a chuck assembly. substantially equal volume and with a minimum Fig. 4 is a transverse vertical sectional view of 50 g of excess material. This chargeis pressed in the a press or preforming assembly-which may be mold by a die which spreads the clay quickly and used for deep molds. evenly over the surface of the mold and afllxes it The were manufactured is known in the art as thereto, the efficiency of the bonding being injiggered dinnerware" as distinguished from the creased by virtue of the pressure applied. This coarser clay ware arts and is plastic, normally 5a adhesive and is fabricated on absorbent molds to which the clay is bonded and adhesively "stuck so thoroughly that the clay and mold may rotate as a unit, the bond being also so thorough that a state of capillarlty is establishd and maintained during the removal of excess material and thereafter as the ware dries. The ware eventually becomes sufiiciently dehydrated through the abstraction of moisture by the mold to shrink and release therefrom. Clay from which i gzered potteryware is made is normally soft and plastic and being inherently ,sticky it has a great afiinity for porous plaster molds and adheres thereto with greater tenacity than to a metal surface. Pressing, as taught herein, improves the bond between the clay and the plaster mold and imparts to the surface in engagement with the mold a greater smoothness, thus making'it easier to finish the ware, besides increasing the density through a closer compacting of the grain structure, thereby adding to the stre th of the product.

The numeral 5 designates a container, preferably of cylindrical form, which may be formed with a flanged bracket lit at one side thereof for adjustable securement to a part of the frame, generally indicated at 6, as by screws la and shims Ob. The clay is fed to the molds by virtue of this apparatus as disclosed in my co-pending application Serial No. 32,753, the feeder being arranged to deposit and segregate a gob of clay on the mold.

Mounted in transverse alignment relatively to the extruding mechanism are means for shaping or preshaping the plasticcharge by pressing the same against the mold which firmly secures the charge thereto whilst spreading the charge from its central position radially over the total ware forming surface of the mold, the mold and die forming in effect a molding chamber when in cooperation, substantially closed by ring 44 as hereinafter described and conforms the charge to the shape of the mold and under a pressure that is substantially equally distributed over the clay, preferably comprising in the present instance a cylindrical plunger 31 having screw-threads 38 formed on its lower extremity, for removable and adjustable application of an annular press head or member 39, as shown in section in Fig. 1, also having lower inner screw threads 40, for removable and adjustable application of an annular press plate 4| having a suitably shaped lower surface or face, a chamber being formed above this press plate, as at 42. This chamber may have introduced therein and circulated 'therethrough various mediums such as hot or cold air, water, oil or other fluid or heating, cooling or lubricating mediums, and likewise, the press plate 4| may be formed of any suitable material and manner, as for instance porous, or have openings therein, so that the fluid or other medium may saturate or exude onto the plastic charge. To enable introduction and circulation of such medium as may be desired, I prefer to form the plunger with longitudinal bores .3 leading into said chamber and suitable fiexible conveying members may be connected with these bores at the upper extremity of the plunger. One advantage of the chamber 42 is that by introduction of a suitable fluid or lubricating medium the charge will more easily separate from the press plate or will not adhere thereto when the latter is raised, thus insuring retention of the clay on the mold and preventing any tendency toward rupture of the firm bond mixture which will enhance the finish of the article of pottery or even a coloring fluid, the many advantages appertaining to this chamber being obvious to those skilled in the art.

Slidably mounted and rotatable on the lower 5 extremity of the plunger 31 over the press head 38 and plate 4| is a charge-confining member in the form of an annular ring or sleeve 44 of suitable shape, preferably of the form shown in section in Fig. 1, a spring 45 being loosely mounted on the plunger 31 above said sleeve and adJustably retained in position by means, of a collar I and set screw 41. To retract or raise the press head and its assembly, a spring 48 may be loosely mounted on the upper portion of the plunger l1 l5 by means of screws 52a. passing through enlarged or slotted openings 52b in a flange 52 and threaded into the frame 0. Shims He may be provided so that the press or preforming assembly isadjustable in all directions.

It will be seen from the foregoing description of the preforming assembly that in operation the annular press sleeve or ring will first encounter the rim or outer edge of the mold and prevent the clay or plastic charge from being pressed out over the side of the mold, the spring 45 being adjustable on the plunger to regulate the pressure necessary for the press ring M to properly perform its function. The press head I! and plate ll continue to descend, spreading the clay radially from its central position toward the brim of the as mold, and preform the charge, securely bonding the clay to the mold by pressure, or may place it in final form, and then elevates followed by the press ring, and the charge is then ready for the profile and trimmer or iiggering operation, or it may then be considered in final form. Fig. 1 discloses a means for charging molds with plastic clay, the clay being applied to the central zone of the mold as shown in an amount sufiicient to form a piece of ware. structure of this preforming assembly could be varied without departing from the scope of the invention, the construction illustrated. being simply apreferred means for accomplishing the desired operation.

Various means could be adopted to operate the press or preforming means,but I prefer to employ cam devices arranged on a common drive shaft I9, Fig. 2, rotatably mounted in bearings on opposite sides of the frame of the mechanism 5.1

as at GI, and which will be of such extent as to accommodate the number of units in operation. To operate the preforming assembly, I prefer to bifurcate the upper extremity of the plunger 31 and mount therein a cam roller I! on a bear-,

cated extremity of said plunger. This cam roller I2, through the action of the spring 48, continually engages a cam 14, also adJustably mounted on shaft 88 as by a hub II and screw 65 lowermost position on the mold containing the .70

charge of plastic material, to preform the latter. The rising movement of this assembly may be more gradual, the press head 39 and plate II It is obvious that the 0 ing pin 13, extending through the upper bifurfirst leaving the charge and then the'press ring A ll. To prevent rotation of the plunger, I prefer 7;

established. It may also be desirable, in some instances, to inject into the chamber 42 a fiuid or to form a longitudinal groove iIa, therein and insert a screw Ib through the sleeve 5| into said groove.

It may be desirable in some instances to form the lower surface of the press plate ll with grooves or irregularities, particularly in the event the mold is being rotated when the charge is being preformed.

In the present instance I provide a frame, generally indicated at 00, which is slidably or adjustably mounted on supporting rails or members 99, as at Ma, the frame 90 having pivot bearings I00, which rotatably receive spindles IN, the latter terminating in chucks I02, adapted to support or carry the mold while the latter is in position under the preforming assembly. In the present instance an independent motive means as at I03 is provided for rotating the spindles MI and chucks I02, but these spindles could be rotated uniformly or separately by cams or otherwise if desired. The spindle IOI has a reduced portion or neck I04, which fits into a cross fork I05. A separate cross fork may be provided for each spindle and adjustably connected by nutted bolts I00 and shims I00a, so that the spindles and chucks'may be disposed at varying elevations. However, in this instance I show the cross forks adjustably connected and controlled as to vertical movement by the pitman rod 93, which. extends through one of the cross forks and is provided with supporting and adjusting nuts above and below the same, as at I01. The pitman 93 extends downwardly through a sleeve I00 and is pivoted as at I09 to one extremity of a lever or bar IIO, preferably disposed substantially horizontally and having a cam roller III rotatably mounted at its opposite extremity, said lever IIO being adjustably fulcrumed as at I ma. The foregoing structure may be readily understood by referring to my Patent No. 1,757,132.

A main drive shaft II2, extending to a suit able source of power, not shown, is provided In the present instance and may have bearing at opposite sides of the frame of the mechanism. This shaft will obviously be of such length as to accommodate the number of units in service, and in the present instance carries the cams for moving the trays and for raising and lowering the spindle IM and chuck bearing the molds. For moving the trays to bring the molds to and remove the molds from the vicinity of the press, it is preferred to use a cam H3 at each side of the track, adjustably mounted on the shaft I I2 as by a hub H4 and screw II5. Each cam is preferably formed with a track I IS. A lever or bar III is adjustably pivoted at its lower extremity as at IIO to an adjustable bracket H011 secured by screws 0b to the rail 09 and has a cam roller H9 rotatably mounted thereon and moving in the track H0. The upper extremity of the lever III has mounted therein a bearing pin or small trunnion I20, and mounted on this trunnion is an adjustable pawl I2I, which rides over the tray trunnions 91 on the backward movement of the lever III and drops by gravity a sufficient distance to abut against the projecting trunnion, and when" the lever is moved forwardly due to the cam roller moving in the cam track Hi, the conveyor will be moved the distance required in accordance with proper adjustments.

A cam I22 is provided in the present instance 1 to operate the pitman 03, this cam being adjustably mounted on the shaft II2 as by a hub I23 and screw I24. This cam may be of any suitable shape and the roller III on the lever IIO, which is adjustably fulcrumed as at 0:1, continually engages said cam, to thereby actuate the pitman 03 when thecam is rotated.

Power may be transmitted from the shaft II2 to the shaft 50 by means of pulleys or sheaves I25 and flexible members or belts I20, and likewise, a flexible member or belt I03a may be provided for the motor I03 and adjustably connected by means of a cone pulley I03b. The motor I21 may be provided with any appropriate rheostat or speed regulating means as at I2'Ia. The shaft I I2 may rotatably extend through and have bearing in a supporting bracket 81, which may be formed integral with or be attached to the frame 90. A bracket is shown at both ends of the chuck and spindle mechanism or frame so that the shaft and cam mechanism may be mounted at either end as found convenient or desirable.

During the preforming operation the molds may or may not be rotated, but ordinarily during this phase of the cycle of operations the chuck may be adjusted so as to raise sufiiciently to afford a firm support for the mold while the press head, plate and press ring descend, and the motor I03 may bedisconnected from the spindle or need not be operated. In case the mold is rotated, it may be desirable to rotate the press ring also to prevent wearing away of the outer edge of the mold and the press ring is adapted to be mounted so as to rotate with the mold if desired.

When the mold with the segregated charge thereon is disposed under the press head, the

annular press ring 44 will descend and first contact with the rim of the mold and prevent the charge from being pressed beyond the edge of the mold, and the press head 39 and plat 4| will then descend and preform or press the charge in or on the mold. Some of the advantages of the chamber 42 have been heretofore explained, and this chamber will of course descend and function at this time with the press head 30 and plate 4|. As has also been heretofore explained, the chuck and spindle may be raised and lowered or rotated as desired during this preforming operation. The press assembly then rises and the mold with its charge may then be considered as finished or ready for the profile and trimmer or jiggering operation.

Fig. 3 shows a modification in press structure which I prefer to employ in the use of molds such, for instance, as are used in the manufactiire of bowls, cups, etc.

To accommodate the press or preforming means to this type of mold, a press ring as at a,.Fig. 4, maybe used and a press head as at 39a having a chamber 42a, which will serve for the introduction and circulation of fluid or other mediums as described in connection with the chamber 42. The side and bottom walls of the press head may be made porous or otherwise as specified in connection with the press plate 4|.

The jiggering assembly may be of any suitable type adapted for molds of this form, but I prefer to use a profile and trimmer assembly as disclosed in my reissue application Serial No. 32,753.

In this instance of producing hollow ware, the press head is comparable to a plunger and in effect the action is to press out a blank having an approximation of final ware form which is mechanically bonded to the mold in a manner as to prevent air entrapment and promote efficient capillary action, this step coming between the to finished green stage.

The mold when shifted under the press head and the press then operates to-press the charge, engaging the exposed surface thereof and spreading the clay to the desired shape and conforming its lower or mold-contacting surface to the mold contour whilst adhesively bonding it thereto, the charge confining member or ring limitingv the radial expansion of the charge. The mold with the formed charge thereon may then be advanced and rotated in operative adjacency to the profile and trimmer to put the finishing touches to the ware and enhance its finish.

I claim:

1. In mechanism of the class specified for molding clay on molds, clay forming means comprising a body having a chamber therein and a clay engaging surface, and means for co-operation with the rim of a mold to limit the radial spread of the clay. V

A 2. In mechanism of the class specified, means for conforming a charge of plastic material to the contour of a mold, comprising a plunger. a press head removably and adJustably applied to said plunger, an annular press and adJustably applied to said plunger and slidable over'said head, and a press plate removably and adiustably mounted on the lower extremity of the press head and forming a chamber between the said press plate and press head.

3. In mechanism of the class specified, means for preforming a charge of plastic material, comprising a plunger, a press head removably and adjustably applied to said plunger, an annular press ring removably applied over said press head,

.and a press plate removably and adjustably mounted on the lower extremity of the press head and forming a chamber between the said press plate and press head, the said plunger embodying means for conveying a fluid medium to said chamber.

4. In apparatus for applying plastic clay to iiggering molds and preforming said clay thereon, the combination with a mold and press member, of an annular resiliently mounted charge confining member'encompassing and having rel- ,ative movement with said press member and adapted to co-operatewith the mold to limit the radial expansion of a clay charge relatively to the mold surface.

5. In a preforming mechanism for applying clay to jiggering molds made of plaster, a plunger, a chambered preforming press head connected to said plunger operable to spread clay over the molding surface of. the jiggering molds and bond the same thereto and means for supporting said molds.

6. A method of applying clay to-Jlggexing molds made of plaster and forming the same to a blank suitable for 'jiggering which comprises, laying a charge of clay on the surface of the mold in substantially the center of distribution of the molding surface and then squeezing the clay against the mold at a pressure value sufiicient to fiow the clay without breaking the mold, spreading the clay by this action progressively to at least the brim zone of the molding surface and bonding it thereto, thereby establishing a state of capillarity for the abstraction of moisture from the clay, the clay releasing from said mold when said clay dries. V

'7. The method of preparing clay bodies for iiggering which comprises applying a charge of clay to a plaster mold}: pressing the charge of clay ring also removably- 21,872 step of charging the mold and jiggering the clay between the mold and a non-rotatable matrix'to now the clay over them forming surface of the mold and repelling the clayfrom the matrix, said clay being bonded to said mold and releasing therefrom when said clay has dried.

8. In a preforming press for applying charges of plastic material to plaster pottery ware molds, a plunger and a chambered press head connected thereto together with a mold'support and means for causing relative movement between said plunger and said mold support.

9. In mechanism of the class specified, preforming and conforming. means comprising a plunger having an enlarged head with a chamber therein. and means slidable on the head for co- .operating with the rim of a mold to confine a charge of plastic material.

10. In mechanism of the class specified, means for cooperating with a mold to preform a charge of plastic material, comprising a plunger having an enlarged press head, and a press plate removably and adiustably applied to the bottom portion of said head. 7

11. A method of coating the forming surface of a plaster iiggering mold with clay to form a jiggering bat which comprises, extruding a quantity of clay through an orifice, segregating a charge of, clay therefrom said charge being deposited upon the molding surface of a mold, said charge covering only a portion of said surface but containing a sufficient volume of plastic material to cover the entire molding surface when spread out and then spreading out the material as aforesaid by applying pressure thereto axially of the mold with a non-adhesive die thereby adhesively bonding the material to the molding surface and commencing the capillary abstraction offiuid from the material, the bond thus created between the mold and clay being maintained when pressure is released by withdrawal of said die from the plastic material.

12. A method of coating the surface of a plaster ilggering mold with plastic material preparatory to jiggering which comprises. app y ng a body of plastic material to the of distribution of a molding surface of a old and then spreading out the material by applying pressure thereto axially ofthe moldthereby adhesively bonding the material to the molding surface and commencing the capillary abstraction of fluid from the material and maintaining the bond thus created by applying fiu'id to the surface of the material opposite that bonded to the mold.

13. In mechanism of the class specified, means for preforming a charge of plastic material, comprising a plunger and a chambered press head connected to said plunger.

14. In the mechanism of the class specified, the combination with a rotating mold and press member, of an annular rotatable charge-confining member adapted to cooperate with the mold to limit the radial expansion of a charge of plastic material.

p'reformer to thereby progressively spread clay over the forming surface of the mold and adhesively bond the clay thereto and means engageable with the mold incident to cooperation with the preformer for exerting a yieldable pressure thereon in the brim zone of the mold during the spreading operation.

16. In a machine for preforming charges of clay preparatory to jiggering, the combination of a plaster jiggering mold and a non-rotatable former operable to squeeze the charge of clay and progressively spread the same over the molding surface of the mold, a mold lifter in which said mold is removably disposed and means com- 10 prising a transifer member having an open seat in which the mold is disposed for transporting the mold to and from the said support.

17. In apparatus for preforming charges of clay preparatory to Jiggering, the combination which comprises, a mold carrier having an open seat in which a mold is disposed, a preforming die, a mold litter arranged in registration with said die, means for intermittently moving said mold carrier to bring the mold into registration with the mold lifter, a support for said die, a cam for reciprocating said die support and die and means for raising said mold lifter to raise the mold from said carrier, said die having a molding surface substantially co-extensive with the molding surface of the mold and being adapted to press and progressively spread clay over the forming surface of the mold, and means for rendering said die non-adhesive to clay.

WILLIAM J. MILLER. 

